/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.harmony.luni.util;
public class BinarySearch {
/**
* Search the sorted characters in the string and return an exact index or
* -1.
*
* @param data
* the String to search
* @param value
* the character to search for
* @return the matching index, or -1
*/
public static int binarySearch(String data, char value) {
int low = 0, high = data.length() - 1;
while (low <= high) {
int mid = (low + high) >> 1;
char target = data.charAt(mid);
if (value == target)
return mid;
else if (value < target)
high = mid - 1;
else
low = mid + 1;
}
return -1;
}
/**
* Search the sorted characters in the string and return the nearest index.
*
* @param data
* the String to search
* @param c
* the character to search for
* @return the nearest index
*/
public static int binarySearchRange(String data, char c) {
char value = 0;
int low = 0, mid = -1, high = data.length() - 1;
while (low <= high) {
mid = (low + high) >> 1;
value = data.charAt(mid);
if (c > value)
low = mid + 1;
else if (c == value)
return mid;
else
high = mid - 1;
}
return mid - (c < value ? 1 : 0);
}
}